Vortex core eccentricity and passive control for separation performance enhancement of a novel circumfluent cyclone separator

We have proposed a circumfluent cyclone separator (CCS) that features a concentric internal cylinder and a gas–solid inlet located at the bottom of the separator shell, as opposed to the conventional cyclone design with the inlet at the upper part. The objective of this study is to investigate the eccentricity of the vortex core within CCSs, its impact on separation performance, and to propose a vortex control method for enhancement of separation efficiency. Our research findings indicate that the eccentricity of the vortex core varies with the vertical position, with the maximum eccentricity observed at the bottom of the cone. Increasing the inlet gas velocity (Uin) results in an elongation of the vortex length and a decrease in the eccentricity of the vortex core. These observations suggest that a high level of vortex core eccentricity negatively affects the separation performance of the CCS. To address this issue, we propose a passive control method to reduce vortex oscillations and enhance collection efficiency. By incorporating a central tube within the CCS, we effectively reduce the eccentricity of the vortex core and alter the characteristics of the power spectral density plot of the instantaneous velocity. Importantly, the addition of a 4–5 mm diameter tube enables the CCS to achieve similar separation efficiency for small particles at a Uin of 18 m/s, compared to the CCS without a central tube operating at a Uin of 24 m/s. Furthermore, the central tube configuration reduces the associated pressure drop by 50%. These findings highlight the effectiveness of vortex control mechanisms in enhancing the separation performance of CCS and other cyclone designs.